1. Field of the Invention
The present invention relates to an interface device that seeks to modify the natural distribution of a ski over the surface on which it slides.
2. Description of Background and Other Information
Skis used for alpine skiing are made up of relatively long beams on which the boots of the skier are retained by front and rear binding elements. The boots and the binding elements are located approximately in the middle zone of the ski.
In the resting position, a ski has a natural camber by which the middle zone is naturally raised relative to the front end of the ski, or tip, and the rear end of the ski, or heel. Furthermore, a ski has a flexibility which depends on its internal structure. During skiing, the ski is elastically deformed in response to the various stresses to which it is subjected by the skier, but also by the terrain on which it slides.
Interface devices exist that are interposed between the binding elements and the ski. Such interfaces are known, for example, from the patent publications such as International Patent Publication No. WO 83/03360, European Patent Publication No. 492,658 and European Patent Publication No. 409,749. These devices modify the flexibility of the beam of the ski by stiffening it or by having a damping effect. However, these devices act passively; that is, they react only to a predetermined flexion of the ski.
Another device of this type is known from French Patent Publication No. 2,689,775. The device disclosed therein includes a longitudinal beam raised relative to the ski. The rear end of the beam is solid with the ski, and its front end is joined by a block of shock absorbing material that undergoes shear stress. This device damps the flexing deformations of the ski. It also damps the boot vertically. However, damping is relatively rigid because of the rigid structure of the beam.
From European Patent Publication No. 530,449, in the name of the present applicant, an interface device is also known that dynamically modifies the distribution of pressure of the ski on the snow, as a function of the vertical stresses that the skier exerts on his or her skis. This device includes a vertically movable sensor that transmits the vertical stresses that it senses, originating in the boot, to the base of the front binding element. In one of the embodiments, the stresses are transmitted by way of a rocking or pivoting device and a substantially horizontal linkage plate is pivotally connected on one side to the rocking device and on the other to the base of the binding.
In an improvement made by the present applicant, the linkage plate is constructed like a toggle, which is closed by the boot and which opens on its own as soon as the boot is released.
Another improvement to this device consists of placing one or more prestressed springs between the rocking device and the base of the binding element, which springs absorb the excessive stresses that the sensor transmits to the base. By breaking, the toggle eliminates the reaction that the prestress induces in the ski as soon as the boot is released from its binding elements that retain it.
The attempt has been made to simplify the structure of this interface device, which is relatively complex, especially because of the presence of the rocker and its surroundings, by obtaining better vertical damping qualities than those of the device disclosed in French Patent Publication No. 2,689,775.